Change in coreboot[master]: util/cbmem: Rebase to handle negative timestamps

[Bora Guvendik (Code Review)]

Bora Guvendik has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/59555 )

Change subject: util/cbmem: Rebase to handle negative timestamps
......................................................................

util/cbmem: Rebase to handle negative timestamps

Rebase all of the timestamps to the lowest(negative) value in the list
when displaying them.

TEST=Boot to OS after adding negative timestamps, cbmem -t

timestamp_add(TS_ME_BOOT_STALL_DONE, 0 - ts[6]);
timestamp_add(TS_ME_ICC_CONFIG_START, 0 - ts[7]);
timestamp_add(TS_ME_HOST_BOOT_PREP_DONE, 0 - ts[10]);
timestamp_add(TS_ME_RECEIVED_CRDA_FROM_PMC, 0 - ts[19]);

0:1st timestamp                                     0
 944:CSE sent 'Boot Stall Done' to PMC                 296,000
 945:CSE started to handle ICC configuration           303,000 (7,000)
 946:CSE sent 'Host BIOS Prep Done' to PMC             308,000 (5,000)
 947:CSE received 'CPU Reset Done Ack sent' from PMC   1,074,000 (766,000)
  11:start of bootblock                                1,101,606 (27,606)
  12:end of bootblock                                  1,161,989 (60,382)

Signed-off-by: Bora Guvendik 
Change-Id: I7eb519c360e066d48dde205401e4ccd3b0b3d8a5
---
M util/cbmem/cbmem.c
1 file changed, 49 insertions(+), 9 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/55/59555/1

diff --git a/util/cbmem/cbmem.c b/util/cbmem/cbmem.c
index 085e004..5aec7fd 100644
--- a/util/cbmem/cbmem.c
+++ b/util/cbmem/cbmem.c
@@ -589,6 +589,39 @@
    return 0;
 }

+static void rebase_timestamp_entries(struct timestamp_table *sorted_tst_p,
+							uint32_t num_entries)
+{
+	uint64_t rebase_delta;
+	struct timestamp_entry *tse;
+
+	if (!sorted_tst_p || num_entries <= 0)
+		return;
+
+	if (sorted_tst_p->entries[0].entry_stamp >= 0)
+		return;
+
+	rebase_delta = 0 - sorted_tst_p->entries[0].entry_stamp;
+
+	if (rebase_delta > sorted_tst_p->base_time)
+		sorted_tst_p->base_time = 0;
+	else
+		sorted_tst_p->base_time -= rebase_delta;
+
+	for (uint32_t i = 0; i < num_entries; i++) {
+                tse = &sorted_tst_p->entries[i];
+
+                /* Rebase all timestamps. */
+		if (tse->entry_stamp > 0)
+			tse->entry_stamp += rebase_delta;
+		else
+			tse->entry_stamp = 0 - tse->entry_stamp;
+	}
+
+	qsort(&sorted_tst_p->entries[0], sorted_tst_p->num_entries,
+		sizeof(struct timestamp_entry), compare_timestamp_entries);
+}
+
 /* dump the timestamp table */
 static void dump_timestamps(int mach_readable)
 {
@@ -621,15 +654,6 @@
    if (!tst_p)
    	die("Unable to map full timestamp table\n");

-	/* Report the base time within the table. */
-	prev_stamp = 0;
-	if (mach_readable)
-		timestamp_print_parseable_entry(0,  tst_p->base_time,
-						prev_stamp);
-	else
-		timestamp_print_entry(0,  tst_p->base_time, prev_stamp);
-	prev_stamp = tst_p->base_time;
-
    sorted_tst_p = malloc(size);
    if (!sorted_tst_p)
    	die("Failed to allocate memory");
@@ -638,6 +662,22 @@
    qsort(&sorted_tst_p->entries[0], sorted_tst_p->num_entries,
          sizeof(struct timestamp_entry), compare_timestamp_entries);

+	/*
+	 * If there are negative timestamp entries, rebase all of the
+	 * timestamps to the lowest one in the list.
+	 */
+	if (sorted_tst_p->entries[0].entry_stamp < 0)
+		rebase_timestamp_entries(sorted_tst_p, sorted_tst_p->num_entries);
+
+	/* Report the base time within the table. */
+	prev_stamp = 0;
+	if (mach_readable)
+		timestamp_print_parseable_entry(0,  sorted_tst_p->base_time,
+						prev_stamp);
+	else
+		timestamp_print_entry(0,  sorted_tst_p->base_time, prev_stamp);
+	prev_stamp = sorted_tst_p->base_time;
+
    total_time = 0;
    for (uint32_t i = 0; i < sorted_tst_p->num_entries; i++) {
    	uint64_t stamp;